this thread has been made before, sorry someone beat you to the punch. but otherwise, I'd say it was. . .. Archeopteryx! Evolution/genetic mutation as an egg, thus making a chicken. Easy question.
I have heard this question about 20 million times. It is hard to answer because the egg needs to come before the chicken, because the chicken hatches from the egg. But the chicken needs to come before the egg, becuase the chicken lays the egg.
A creature that is not yet definable as a chicken (hen) lays an egg. From that bird egg, a chicken hatches. This chicken grows up and lays its own egg, thus the first chicken lays the first chicken egg, while it hatched from an egg that came before.
So, because the question does not specify that it is a chicken egg, the egg definitely came first.
Unless you believe that Creationism is facts.
Anyway, I'll be locking this now because there isn't gonna be any truly finite answers, and the topic have been created before. It's not gonna make any progress.